None N asked: Will a medium make a good fit for a person that sometimes can wear a large I'm a 9/10 and a 34C
sheila s: yes thats my situation. I didn't want it to be gappy under the arm. So I think you will be fine.
Steffany B: Most likely it would especially since you're in between sizes! I bought a small and I can usually wear a small or medium depending on the fit! I'm about 130 and 34c also and the small fits perfect!